1. Field of the Invention
The present invention is in the field of optical instruments including binocular field glasses and colorized glasses such as sunglasses or the like. The invention pertains particularly to methods and apparatus providing improved visual capabilities of optical instruments.
2. Discussion of the State of the Art
Classical Galilean binoculars have the advantage over modern prism binoculars of producing an erect virtual image for a user and are not equipped with prisms or other devices. The entrance pupil of the eye must coincide with the optical axis of the Galilean telescope or binocular for successful viewing. The construction of Galilean binoculars and the implementation of optics therein enable a field of view which may be rather limited.
A common limitation of standard Galilean binoculars and one that is not necessarily limited to Galilean binoculars is that it may be very difficult to see clearly through them when using them to view certain action-intense sporting events. This is due in part to the small exit pupil size and to specific eye relief limitations. One with skill in the art of binocular viewing may appreciate these limitations by simply holding a binocular up to a source of light and away from the user's face. The small circular exit pupils may then be observed as de-magnified images of the front objectives within the eye lenses of Galilean binoculars, or illuminated in mid air at a short fixed distance behind the eye lenses of modern prism binoculars. That short fixed distance is termed the binocular “eye relief” in the art and may vary somewhat among different binocular designs. To use these binocular systems successfully, it is necessary to place both pupils of ones eyes directly in line with these small exit pupils and exactly at the precise fixed distance behind the eye lenses with modern prism binoculars. If this were not done, the user would not see anything. Logically then, maintaining that position with respect to keeping the pupils at the exit pupil locations is very difficult during fast moving sports activities. Wearing of eyeglasses or sunglasses may also severely limit successful viewing.
Typically, the objective lenses of Galilean binoculars are positive achromatic doublets each comprised of a positive element made of a crown glass or acrylic plastic material and also a negative element to correct color aberrations made of a flint glass or polycarbonate type of plastic material. The positive element is very expensive to manufacture using plastic molding techniques especially in large diameter short focal lengths. Visual limitations occur because of a fact that the thin peripheral edges of the positive element cool more quickly than the thick centers of the lens and so the surface “slumps” or becomes distorted and therefore less able to produce sharp contrast and clear imaging.
Still other fixed conditions associated with using a Galilean or a more modern binocular system may be construed to be limitations for which a solution may be provided. For example, it is generally known that one must continually refocus a typical binocular system to compensate for the varying object distance created by the moving players of the sporting event. Also known is that the binocular system must be adjusted to a proper eye separation distance between a user's eyes. Still other limitations may exist such as lack of color contrast imaging enhancements and chromatic imaging adjustments which are typically not available in an affordable and practical manner to most standard binocular systems.
Binoculars are useful in magnifying the appearance of distant objects and often utilize anti-reflection or other coatings to reduce “glare” that may occur under certain use conditions. However, the color contrast of images is generally always fixed by the lens properties and the results thereof may be far from optimum for viewing substantial detail of images under a variety of conditions.
Colored or tinted glasses, like sunglasses, for example, are used to diminish light intensity for comfort's sake, and are also worn for appearance sake. Sunglasses are often provided with colored lenses for appearance. Colored lenses may also be used to provide enhanced contrast in objects viewed such as with ordinary “driving glasses” or “shooters' glasses” where orange or yellow tinted lenses are employed to improve visual contrast by reducing the blue end of the color spectrum. However, these colored glasses provide only limited vision enhancement because the contrast is limited by the fixed color of the lenses employed.
Therefore, what is clearly needed in the art are methods and apparatus for improving the visual capabilities of optical instruments including binocular systems and, in some cases, colored glasses or sunglasses. Such improvements and methods of implementation and use would provide more reliable and entertaining viewing through such optical instruments without requiring significant alteration or expense related to existing designs and configurations.